FDA warns MS patients about risky stent treatment

WASHINGTON (Reuters) - U.S. drug regulators are warning people with multiple sclerosis to avoid an experimental treatment that props open internal veins in the neck and chest, because it can cause death or serious injury.

The Food and Drug Administration on Thursday said at least two people died from the procedure, which uses stents or balloon angioplasties to widen veins that connect the brain and spinal cord to the heart. One person was permanently paralyzed and others had bleeding in the brain and suffered strokes, blood clots or other side effects.

It is unknown how many people received the treatment and how many had problems, as stents and angioplasties are not approved for this use by the FDA, the agency said. Stents are steel mesh coils that can keep arteries open, while balloon angioplasties use a balloon at the tip of a catheter to open blocked blood vessels.

The FDA could not immediately identify the stent models being used in such treatments.

The FDA announcement relates to a controversy that has developed in the multiple sclerosis (MS) community about the causes of the chronic, progressive disorder of the brain and spinal cord.

The disease, which affects about 2.5 million people worldwide and has no cure, attacks the central nervous system and can lead to numbness, paralysis and loss of vision. Drugs that treat the condition can often only prevent relapses or slow its progression.

The underlying cause of MS is unknown, but some researchers believe that although it is typically thought of as a disorder of the immune system, MS may actually be caused by blood vessel changes.

Their theory is that veins bringing blood from the brain and spine back to the heart sometimes become too narrow, making blood leak back into the brain tissue. That could trigger inflammation, eventually causing the balance and muscle problems seen in MS.

Other scientists have not been able to show a link between MS and the condition, which is called chronic cerebrospinal venous insufficiency, or CCSVI, or prove the condition exists at all.

Meanwhile, multiple sclerosis patients scour for new treatments, prompting patient advocacy and research groups to invest in more research studying the link between multiple sclerosis and CCSVI.

"Our position is that the evidence is simply insufficient to determine whether there's a link," said Dr. William Maisel, the deputy director and chief scientist of the FDA's devices division. "We want patients to be aware of the risk associated with the procedure."

The FDA said people who want to try the experimental treatment for MS should only do it while participating in clinical trials.